The Yomiuri newspaper's survey issued on Monday showed that the disapproval rating for Abe's Cabinet rose to 50 percent from early March, compared with 47.5 percent in the Kyodo news agency's survey published on Sunday.

The support rate for the Cabinet showed a slight rise to 42.4 percent in the Kyodo poll, while the Yomiuri poll showed a drop of six points to 42 percent.

The polls followed last week's testimony by ex-finance ministry official Nobuhisa Sagawa, who said neither Abe nor his wife influenced the murky sales of state-owned land to a school operator or the finance ministry's altering of documents about the deal.

The slide in Abe's ratings has clouded his prospects of winning a third three-year term as president of his Liberal Democratic Party, a victory that would set him on track to become Japan's longest-serving premier. Abe has been prime minister since 2012.